1. Field of the Invention
This invention relates to an evaporator device for ice making equipment and to a method of manufacturing the evaporator device. In particular, the invention relates to an evaporator device that does not use brazing or soldering in a manner that leaves brazing or soldering material in contact with the ice making cells.
2. Description of the Prior Art
Evaporator devices generally include an array of ice cells arranged in a grid of horizontal rows and vertical columns and a refrigerant tube that is positioned adjacent the grid to provide cooling during ice making and heating during defrost and harvest.
It is known to construct an ice cell array with thermally conductive metal, such as copper or aluminum. An example of a copper evaporator device is shown in U.S. Pat. No. 4,459,824. The evaporator device, when constructed of copper, is plated with a suitable metal, such as tin or nickel. The plating is required by Natonal Sanitation Foundation codes, which prohibit the use of copper parts in contact with food products. The plating process results in waste products that need to be handled with environmentally acceptable procedures. In addition, plating degradation can occur at solder fillets used in the construction of the array of cells or their connection to other parts over which the water used in the ice making process may flow. This can result in a formation of copper oxides that could contaminate the ice.
Examples of evaporator devices that use aluminum parts to construct the ice cell array are shown in U.S. Pat. Nos. 3,430,452, 5,129,237 and 5,193,357. For instance, U.S. Pat. No. 5,193,357 discloses a plurality of horizontal integral aluminum pieces arranged side by side to form a grid of ice cells. However, the back of each ice cell contains a gap that is filled entirely or partially with brazing material. Brazing material or soldering material can deteriorate over time, thereby resulting in unreliability. Moreover, the evaporator device construction is limited to one-sided ice cell arrays.
U.S. Pat. No. 5,129,237 discloses an evaporator device constructed of a base plate from which extend row wide fins. Vertical fins must be connected to the row wide fins to form a grid of ice cells. Conventional techniques have included notches. Notch connections are susceptible to loosening and, therefore, present a quality issue. If the notch connection is strengthened by brazing or soldering, the above noted disadvantages will result.
Thus, there is a need for an evaporator device that does not have ice cells formed with copper, brazing material or soldering material.
There is also a need for an evaporator device that has secure fastenings without the use of brazing or soldering.